A newly manufactured automobile body is typically painted with the doors installed. During the painting process, the doors are moved from a closed position to an open position to facilitate the painting of an interior of the automobile body. The doors are returned to the closed position when the painting of the interior of the automobile body is completed. Robotic devices featuring a specially adapted tool disposed at the end of an articulated arm are typically employed to grip the doors during the opening and closing process. The automobile hood, tailgate and trunk cover can also be installed on the automobile body and must also be opened and closed during the painting process, similar to the doors.
One approach to gripping the doors has been the use of a magnetic tool adapted to attract the door to move to the open position and release the door to permit a closure thereof. One such magnetic tool is disclosed in commonly owned U.S. Pat. No. 5,941,679, hereby incorporated herein by reference in its entirety. The prior art magnetic tools typically have a fixed magnetic force at an outer surface of the tool to contact the door of the automobile. The fixed magnetic force limits the usability of the tools on varying body styles of doors or variations in the pull strength and release strength required to open and close a particular body style door. The modern automotive paint line is typically adapted to receive multiple automotive body styles. The magnetic tooling of the prior art does not provide the necessary flexibility in magnetic force to accommodate the different automotive body styles.
The magnetic force of the current magnetic tools is established by manually configuring the tool to achieve the desired magnetic force. The number of magnets, strength of the magnets, and distance between the magnets and the outer surface of the tool can all be varied to achieve a desired force to open and close a particular body style door. If the tool has insufficient magnetic force, the tool may prematurely release the door during the opening or closing process, which interferes with the painting process. If the magnetic force is too high, the pull force required to release the tool from the door may result in undesirable damage to the tool or the door.
Additionally, the magnetic tools of the prior art typically include a number of metal components. An electrostatic painting process is typically employed in the painting of newly manufactured automobile bodies. The metallic components of the tools attract the charged paint droplets and results in increased cleaning requirements for the tooling. Accordingly, the metal components must be electrically grounded.
It would be desirable to develop a magnetic tool for a robotic arm having a magnetic force that can be adjusted, wherein the tool is adapted to minimize an accumulation of paint on the tool.